"I keep all the Roma teammates in my heart, as I'll never forget the city and its fans, who did so much for me. Now I am at Milan and very proud to be part of this club," he said.
"I had seven marvellous years at Roma and it's partly thanks to them that I grew as a man and a player to earn this opportunity with Milan.
"It was my choice, as I could've joined Real Madrid this summer. In the past I chose Roma ahead of Manchester United. I dreamed of a club like this since childhood and it's an important shop window, so I can hope to earn a place in the France squad for Euro 2012."